The sterilization of a container to be filled is, as well as the actual filling procedure, an essential process step, in particular in an aseptic filling plant. The possible forms of sterilization vary with respect to the disinfection agents and the performance of the process. What is common to them all, however, is the fact that the destroying action is carried out on the basis of chemical processes. More recent developments known from the prior art differ from these and make use of ionizing radiation in order to achieve a reduction in the germs. In the majority of applications this radiation comprises accelerated charge carriers and, in particular, accelerated electrons which are produced in a corresponding plant and are introduced into the container to be sterilized. The advantage of this procedure consists in the reduction or avoidance of the use of chemical substances. Nevertheless these apparatus, however, have acceleration plants which are in part not yet established and, as a result, are expensive and, in addition, they have a relatively complicated circuitry and monitoring. In addition, on account of the stray radiation which occurs a screen has to be present around the entire plant or around individual parts of this plant.
An apparatus for the sterilization of containers is known from DE 10 2009 008633 A1. In this case the containers are conveyed along a pre-set conveying path, more precisely through a treatment room. Here sterilization is carried out by acting upon the containers with electrons, a sterilization device of this type having a generating device for generating the electrons, as well as an accelerating device in order to accelerate the electrons generated by the generating device in the direction of the containers present in the treatment room. In this case a gas pressure inside the treatment room is below the gas pressure outside the treatment room. It is therefore suggested that the electrons should be accelerated in a region which is under a relatively low pressure in order to increase the reach of these electrons in this way.
The present systems which are available on the market and which are used for the sterilization have an electron generation apparatus and a grouping and mechanical solutions to the transmission of the electron beam into the container to be sterilized. Expressed more precisely, in the case of these plants a beam finger is usually introduced into the containers and the electrons are accelerated through this beam finger in the direction of an outlet window and they then issue out of the outlet window and onto the inner wall of the containers. In order to ensure the effect and transmission of the beam, the electrons generally have to be accelerated to a high degree. The acceleration voltage required for this amounts to up to 150 kV. The kinetic energy of the electrons is increased accordingly and undesired radioactive or X-ray radiation is produced to the same degree.
A further drawback of previous plants and apparatuses for the generation of electron beams is the problem of conveying the electrons from the generator source to the site of operation. The molecules present in the interspace, which occur in the air or in the existing outlet window, obstruct the reach of electron beams to a significant degree. As a consequence the acceleration of the electrons has to be adapted, this being a step which in turn will increase the size, the complexity, the risk potential and the screening, as well as the costs of the plant as a whole.
The object of the present invention is therefore to make available a method and an apparatus which avoid the use of very high acceleration voltages. In addition, the costs of a plant of this type for the sterilization of containers should be reduced as a whole.